Various different textile prefabricated articles, also called semi-finished materials and semi-finished articles in the following text, are typically used in the production of fiber reinforced plastic composite materials and products. Particularly, in addition to woven and braided materials, non-woven fleece materials and other textile webs can also be used for the textile semi-finished articles or materials. Subsequently, these semi-finished articles may be processed, packaged, cut or otherwise handled, and combined and connected with each other. The thusly resulting preforms are finally saturated or impregnated with a matrix system (e.g. resin) and then cured generally under elevated pressure and elevated temperature.
Today, textile semi-finished products, such as woven and braided materials, are typically applied or arranged in or on an intermediate carrier at the end of the production process of the textile material, e.g. the weaving or braiding process. In this regard, the intermediate carrier may, for example, be a cylindrical body upon which a braided material is wrapped or wound as an encircling strip. The geometry of such an intermediate carrier body does not serve for preforming or reforming the geometry or configuration of the semifinished material, but instead merely serves as an auxiliary support for transporting and storing the semifinished material.
During the course of the further manufacturing process, the semi-finished material or article is again removed from the intermediate carrier body, and is then processed, handled, or made up as necessary, and is then finally brought into the desired form or configuration of the required preform by carrying out reorienting and reforming of the fiber mass or body of the semi-finished material or article. In this context, several fiber orientations are fixed through the manufacturing process, and can no longer be subsequently influenced or changed thereafter. For this reason, certain component geometries can no longer be achieved using semi-finished articles that have previously been temporarily arranged on intermediate carriers, even if the actual manufacturing process would allow the attainment of such geometries without the limitations imposed by the use of the intermediate carrier.
It is also known to use continuous methods, in which the semi-finished material or article is delivered to the further manufacturing process directly following the web forming process. The possible reorienting and reforming of the textile semi-finished article, however, takes place without having the preceding web forming process actively oriented, configured, or arranged in relation to such a subsequent reorienting or reforming.
An exception exists in the braiding of fiber materials around a core, whereby the core has a desired geometry and has the fiber material braided externally around it, in order to achieve a desired fiber orientation. Thereafter, the utilized core can be removed. The use of cores in this manner, however, only allows certain limited geometries of the semifinished articles produced thereby. Moreover, the geometry and dimensions of the core are limited. A further exception is represented by so-called circular or spiral woven materials in which the length of individual threads of a thread system is variable, whereby a direction change of the semi-finished article in a plane can be achieved.
The fixing of semifinished articles can be carried out with the aid of a binder. The typically utilized binder systems mainly comprise thermoplastic substances, which are applied onto the semi-finished article, for example in a powder form, and are then activated under the influence of a sufficiently elevated temperature. In addition to fixing the fiber orientation, such binder systems can be used to fix the preform in a compacted condition.
In the general field of the braiding techniques, two-dimensional and three-dimensional braiding can be distinguished from each other. Three-dimensional braiding makes it possible to produce semi-finished articles with a defined cross-sectional geometry, which may be altered or changed even during the manufacturing process. By respectively guiding the individual threads of the braid in a manner that is mutually independent from each other, it is possible to produce, for example, L-shaped or U-shaped cross-sections of the semifinished articles. The resulting fiber articles have a configuration or contour that is close to the final contour, and possess a moderate draping characteristic.
Two-dimensional braiding is carried out in so-called circular braiding machines. The semi-finished article resulting thereby is a hose-shaped or tubular braided body, in which it is not possible to introduce fibers or threads that are oriented in the radial direction (90° relative to the surface of the resulting hose or tube). Two-dimensional braided bodies are readily drapable and can be further handled and processed as either a flat or a tubular-shaped semi-finished article. During the braiding process it is possible to achieve defined fiber orientations and semi-finished article geometries by braiding the fibers or threads around a core having a suitable geometry. By introducing stretched or extended fibers (so-called standing or stationary end threads) in the drawing-off direction, the draping ability can be reduced in certain selected spatial directions.